import KernelEx-4.0-RC1

kexcrt/memmem.c

@@ -0,0 +1,52 @@
+/*
+ * memmem.c
+ *
+ * Find a byte string inside a longer byte string
+ *
+ * This uses the "Not So Naive" algorithm, a very simple but
+ * usually effective algorithm, see:
+ *
+ * http://www-igm.univ-mlv.fr/~lecroq/string/
+ */
+
+#include <string.h>
+
+void *memmem(const void *haystack, size_t n, const void *needle, size_t m)
+{
+	const unsigned char *y = (const unsigned char *)haystack;
+	const unsigned char *x = (const unsigned char *)needle;
+
+	size_t j, k, l;
+
+	if (m > n || !m || !n)
+		return NULL;
+
+	if (1 != m) {
+		if (x[0] == x[1]) {
+			k = 2;
+			l = 1;
+		} else {
+			k = 1;
+			l = 2;
+		}
+
+		j = 0;
+		while (j <= n - m) {
+			if (x[1] != y[j + 1]) {
+				j += k;
+			} else {
+				if (!memcmp(x + 2, y + j + 2, m - 2)
+				    && x[0] == y[j])
+					return (void *)&y[j];
+				j += l;
+			}
+		}
+	} else
+		do {
+			if (*y == *x)
+				return (void *)y;
+			y++;
+		} while (--n);
+
+	return NULL;
+}